In fact, EPA reported automakers not just complied with clean car standards in 2014, but over complied by a record margin. Furthermore, light truck fuel economy, including pickups and SUVs, hit an all-time high in 2014 of 20.4 miles per gallon (mpg), a jump of 0.6 mpg.

Thanks to clean car standards, according to the U.S. EPA Fuel Economy Trends report, automobiles sold in 2014 were 5 miles per gallon more fuel efficient than 10 years ago, averaging 24.3 mpg. Had we stalled at 2004 levels, we would have burned 28 billion more gallons of gasoline--costing consumers over $70 billion--and pumped another 300 million metric tons of carbon pollution into the atmosphere annually. That's equivalent to adding another 55 million vehicles to our roads.

Importantly, thanks to well-designed standards, the auto industry can still meet tougher clean car requirements, despite a slight shift to more polluting light trucks. The new EPA data shows that while new vehicles' average fuel economy technically remained flat from 2013 to 2014 (reflecting the shift to light trucks), the average new light duty vehicle still got cleaner, emitting 5 less grams of carbon dioxide (CO2) per mile and the industry over-complied by a record 13 grams per mile. The reasons for this apparent paradox are as follows:

First, the clean car standards themselves automatically adjust to reflect changes in consumer preferences, such as the shift to crossovers and other larger size vehicles. That is, as the nation's vehicle fleet shifts to light trucks and bigger vehicles, the standards get slightly less stringent.

Second, while the combined car and light truck fleet average is weakened by the shift to less efficient light trucks, the light trucks themselves continue to get more fuel efficient and hit a record high of 20.4 mpg, a jump of 0.6 mpg --the second-largest jump over in three decades.

Finally, the fuel economy levels do not take into account additional carbon reductions not captured on the standard fuel economy certification test cycle, such as for improved air conditioning systems and active aerodynamics. These new improvements contribute to further reducing the carbon dioxide pollution by 5 grams per mile.

Automakers are also already deploying the technologies they need to meet future standards. As shown below, 26 percent of the 2015 model year (MY) vehicles produced for the U.S. market meet 2018 standards, mostly by using conventional gasoline technologies, such as efficient transmissions, direct injection, and turbocharging.

Credit: EPA Fuel Economy Trends: 1975 through 2015

We can expect more clean vehicle technologies to be deployed as the standards continue to tighten. With the arrival of 2016 model year vehicles in showrooms now, we are entering the fourth year of the landmark 2012-2015 standards. Thanks to the standards, consumers are collectively saving billions of dollars at the pump and carbon pollution is being reduced. Clean vehicle standards have put us on a pathway to a cleaner, less oil-dependent future.